title: Exploiting powder X-ray diffraction for direct structure determination in structural biology: the P2X4 receptor trafficking motif YEQGL.
abstract: We report the crystal structure of the 5-residue peptide acetyl-YEQGL-amide, determined directly from powder X-ray diffraction data recorded on a conventional laboratory X-ray powder diffractometer. The YEQGL motif has a known biological role, as a trafficking motif in the C-terminus of mammalian P2X4 receptors. Comparison of the crystal structure of acetyl-YEQGL-amide determined here and that of a complex formed with the μ2 subunit of the clathrin adaptor protein complex AP2 reported previously, reveals differences in conformational properties, although there are nevertheless similarities concerning aspects of the hydrogen-bonding arrangement and the hydrophobic environment of the leucine sidechain. Our results demonstrate the potential for exploiting modern powder X-ray diffraction methodology to achieve complete structure determination of materials of biological interest that do not crystallize as single crystals of suitable size and quality for single-crystal X-ray diffraction.
authors.affiliation: School of Chemistry, Cardiff University, Park Place, Wales, United Kingdom.
authors.forename: Kotaro
authors.initials: K
authors.lastname: Fujii
authors.forename: Mark T
authors.initials: MT
authors.lastname: Young
authors.forename: Kenneth D M
authors.initials: KD
authors.lastname: Harris
mesh_terms: D020816:Amino Acid Motifs; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010455:Peptides / Q000737:chemistry / Q000235:genetics; D033362:Powder Diffraction / Q000379:methods*; D011487:Protein Conformation; D058848:Receptors, Purinergic P2X4 / Q000737:chemistry* / Q000235:genetics*; D014961:X-Ray Diffraction / Q000379:methods*
chemical_list: D010455:Peptides; D058848:Receptors, Purinergic P2X4